This invention relates to the field of spades, in particular those designed for heavy hand field use and particularly suited for gardeners and nurserymen who use the spade essentially every day. The spade should be distinguished from a shovel which is usually used on light unpacked materials. The spade, on the other hand, is designed to be forced into compressed earth and be strong enough to lift out and pry the earth from its settled position. When a spade is used by a nurseryman, it has been found that the blade may wear out before the handle wears out or breaks. In some instances, it appears that the handle has been designed to last only about as long as the spade blade. I propose that if the spade handle is properly designed and constructed, it is essentially indestructable. There are finite limits to the stress that can be applied by an individual and the necessary strength may be constructed into the handle system. I have also observed that none of the prior art spades have a handle designed and constructed for use of two hands at the same time. Having recognized these factors, I have considered the spades in the prior art and have found no devices to satisfy the needs in the industry. A typical spade, although called a shovel in this patent, is described in U.S. Pat. No. 204,897 to J. Johnson. A detachable shovel blade is described in U.S. Pat. No. 348,794 to Z. H. Smith and another shovel that may be taken apart is described in U.S. Pat. No. 701,805 to J. W. Ellison. The limitations on these structures will be apparent to a reader of this disclosure.
The typical spade used by the homeowner uses a wooden handle which is wedged into the socket welded or bolted to the spade blade. For the nurseryman, a wooden handle is not durable enough and not strong enough for his continued use. Manufacturers still offer spades of this construction, but failures are numerous and the nurseryman not only risks the loss of the spade to breakage but also risks personal injury when the break occurs.
The spades of the prior art also do not take into account the general use of the spade when it is forced into the ground by the nurseryman pressing on the footrest step along the top edge of the spade blade. Actually, I have found that the skilled nurseryman cannot place his foot flat on the rest without coming into contact with the tubular handle. Of necessity the nurseryman rests his foot on the outside corner of the top edge with the attendant risk to shoe and self.
It is an object of this invention to provide a spade with a detachable blade.
It is an additional object of this invention to provide a detachment mechanism which provides the strength and durability sufficient to withstand the hard use of a spade in industrial use.
It is an additional object of this invention to provide a spade blade construction which is reinforced and has sufficient strength to stand misuse.
It is an additional object of this invention to construct a spade with a handle system which will be essentially indestructable and with a spade blade that may be replaced when the end of the blade has worn down.
It is a further object of this invention to provide a spade handle that allows easy use of two hands to pry the earth up.
It is an additional object of this invention to provide a spade that allows foot pressure on the foot step of the blade in a sure footed fashion while avoiding interference with the handle during the pressing operation.
It is an additional object of this invention to provide an interlocking attachment system between the spade blade and the handle system which is sufficiently durable and permanent to allow years of use without failure.